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Adjustment Procedures
2715 Spectrum Analyzer Service Manual
5-47
Adjust Video Detector. Adjust L11 as follows:
1. Connect the TSG 95 Video Output to the TVM450 Video Input. Connect the
TVM450’s --20 dB RF TEST Output to the 2715 RF INPUT.
2. Set the TS G 95 to produce a 5-Step Grayscale and set it to the desired video
format (NTSC or PAL).
3. Set the TVM450 output to Channel 4 and the RF level control full counter-
clockwise.
NOTE. Be sure the OFFSET switch on the rear panel of the TVM450 is set to OFF.
4. Check that the VIDEO MODULATION and VIDEO/AUDIO RATIO
controls on the TVM450 are both set to mid range (detent) and that the
AUDIO DEVIATION control is set full counterclockwise.
5. Select the following settings on the 2715:
CENTER FREQUENCY 67.25 MHz
SPAN/DIV 2 MHz
Calibrator Signal OFF
6. Set the signal (visual carrier) to the top graticule with the REF LEVEL ↑ and
↓ controls.
7. Set SPAN to ZERO.
8. Activate the VD DAC TO VIS CARR function by pressing UTIL526.
9. Select the following settings on the test oscilloscope:
Vertical Mode CH 1
CH 1 Volts/Div. 500 mV
CH 1 Coupling DC
Time/Div. 10 s
Trigger Mode Auto
Trigger Source CH 1
Trigger Coupling DC
10. Connect the oscilloscope channel 1 probe to the Video Demod VIDEO TP.
11. Tune L11 until the test oscilloscope displays a video signal as illustrated in
Figure 5--18.
NOTE. It will probably be necessary to adjust the test oscilloscope trigger level
control to obtain a stable display.